The collective of knowledge and understanding of pulmonary rehabilitation has shown that patients with chronic lung diseases (CLD) such as chronic obstructive pulmonary disease (COPD), can live comfortable, productive and enjoyable lives if they can remain active. Patients on long-term home oxygen are limited by the portability of their system. It has been demonstrated that patients with CLD will live longer by using their oxygen continuously and that depriving them of oxygen during exertion may cause dangerous tissue hypoxia (lack of oxygen). As their impairment gradually worsens, these patients live progressively more confined existence. They find it difficult to leave their homes and gradually find themselves limited to living space of a chair or bed. This severely hurts their ability to live quality lives, and they become depressed and a burden to their families. The goal of pulmonary rehabilitation is to reverse this trend, mobilize and make these patients more active. Pulmonary rehabilitation is remarkably effective in meeting this goal.
The physiological goal of oxygen therapy is to maintain arterial oxygen saturation above 90 percent for all living conditions including wakeful rest, sleep and exertion. Because of the unique capacity for hemoglobin on the red blood cell to carry oxygen, little is gained by maintaining oxygen saturation above 90 percent, except to assure that it does not drop below 90 percent. Adding much more oxygen is wasteful and will impose an unnecessary weight burden for the patient using portable oxygen.
The Oxygen consensus
Conferences and the most recent conference of the American Thoracic Society and European Respiratory Society Standards for the Diagnosis and Treatment of COPD have emphasized the importance of maintaining an active lifestyle and the importance of a portable oxygen system.
In response to the need for mobility, coupled with the necessity for oxygen therapy in order to protect the body tissues from tissue hypoxia, there is a need to deliver oxygen to patient more efficiently. Providing adequate supplies of oxygen improves oxygen transport to the muscles, improving both strength and endurance and becoming an essential ingredient in pulmonary rehabilitation. The oxygen therapy apparatus disclosed in U.S. Pat. No. 4,572,177, co-invented by me together with Robert E. Phillips and Ben A. Otsap, teaches an oxygen conservation system. That system is very useful in the conservation of oxygen. This disclosure teaches further advancement in controlling the flow of oxygen to the patient to improve upon alveolar gas exchange and oxygen transport to the exercising muscle.